Lightweight fiber composites hold great promise for the aircraft industry. Fiber composites provide a significant improvement in specific strength and stiffness over conventional metal alloys. Better specific strength and stiffness translates into weight savings, which translates into fuel savings and lower operating costs.
Fiber composites such as carbon fiber reinforced plastic may be used to fabricate fuselages of commercial aircraft. During fabrication by filament winding, a cylindrical mandrel tool is rotated, and resin-impregnated tape is continuously wound onto a layup surface of the rotating tool. Layer after layer of the tape is applied until a layup of the fuselage is formed. The layup is then cured. Openings for windows, passenger doors, and cargo doors are then cut in the fuselage.
Fabrication by automated fiber placement (AFP) is an alternative to filament winding. During AFP, a fiber placement head deposits bundles of fibers (“tows”) onto a rotating mandrel tool. The tows are narrower and more easily manipulated than tape. AFP is most effective when placing material on a curved or contoured surface.
It would be desirable to use AFP to form layups for fuselages of large commercial aircraft. AFP could add extra plies to high stress areas and reduce plies in low stress areas. In addition, AFP could deposit tows at different lengths and orientations to form openings in the layup. This would eliminate the time and effort of cutting openings after the fuselage has been cured.